Frogsleap Farm

Tuesday, December 13, 2011

Fruit Stripes Revisited

2011 was a learning year on many fronts. We’ll be posting about some of what we saw and learned over the next few months. In the first of these new posts we want to share some photos and observations about lateral stripes on tomato fruit, which now appears to be a little more complicated than a simply inherited trait controlled by the dominant allele Fs (as discussed briefly in a 2010 post here: Genetic Control of Stripes in Tomatoes).

Tornado

First of all, the prominence of the lateral fruit stripes can vary greatly. We found a F4 plant with very bold stripes in a purple fruited line that has been segregating for lateral stripes – but until now the stripes have always been subtle. Not this plant. Certainly there may be an environmental effect, though this F4 family segregated for presence and prominence of the lateral stripes. I suspect there may be minor genes that modify Fs, and that the Fs allele has incomplete dominance – i.e. the homozygous Fs/Fs has more prominent stripes than the heterozygous Fs/+. This new line is a very early large fruited type with exceptional flavor. Hopefully we can stabilize this combination of traits this year in the F5. We’re trying to think of an appropriate name for a tomato that originated from a F1 cross made by Bill Jeffers in Indiana, then to a unique F2 segregant we found here at FLF, then to a fabulous F3 plant Mark selected from a large growout in Pennsylvania at Happy Breeze Farm, and finally to the F4 plant Jess found in a row at Baia Nicchia farms in California. Maybe “Tornado”?﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿

Aft/Fs unripe fruit

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Aft/Fs

Last year we reported an accumulation of anthocyanin in lateral fruit stripes of fruit with the Aft phenotype. This was particularly striking in a red/orange fruited beauty from a F2 plant from our 2009 cross OSU Blue x Beauty King (which was nicknamed Siberian Tiger by our friend Dean Slater). Although the Aft phenotype was fixed in the F3 generation, it was difficult to find segregants with the same lateral striping – and we had a lot of plants with several different friends that were looking for this. This pattern was found however in a different OSU Blue x BK F2 line and in a purple fruited F3 tracing to an independent cross we made in 2009. Stabilizing this unique phenotype may be tricky, and again suggests that inheritance of the lateral stripes is a little more complicated than we thought. Note the interesting patterns on some of the F3 lines this year.

Lithium Sunset

When we were visiting Fred Hempel at Baia Nicchia Farms this summer we saw one of his lines, Lithium Sunset, which had the most striking and unusual pattern of lateral fruit stripes we had ever seen. This may or may not involve Fs, it reminds me of a lava lamp. I can’t wait to grow it this year and hopefully cross it to some of our Fs lines. A photo of another unusal Fs phenotype was posted online at the Tomato Depot by our friend Shaun Harris. Shaun found dark green lateral stripes on a GWR fruit – something we haven’t seen before. Very cool indeed.